The present invention relates to the field of power distribution for electronic systems, and more specifically to the generation of a power good signal for a voltage regulator.
Electronic systems require monitoring circuits and signals to ensure that the voltage rails are operating within an appropriate range. Typically, the voltage rails will have a constant direct current (DC) value, with associated alternating current (AC) noise. For this type of supply rail, a voltage reference and comparator circuit may be used to generate a “power good” signal by monitoring the output voltage to determine if it is within the desired range.
For some implementations/loads, it is advantageous to create supply rails having complex output voltages. These supply rails have output voltages that are dependent upon the load current and/or the operating state of the load. Some exemplary implementations of complex output voltages include implementing a load line and/or ACPI power states, and Intel® Speed Step™ technology.
Conventional methods to generate a “power good” signal do not produce accurate results for a voltage regulator (VR) that generates complex output voltages. For a complex output voltage VR, the allowed output voltage range must be so large as to allow voltages outside of the allowed accuracy specifications to be indicated as good signals.